ANACHEM CHAP 11

electrochemical cell

a pair of electrode incobtact with an electrocyte solution

Galvanic /votaic cell

an electrochemical cell, spontaneously produces surrebt or energy when electrodes are externally connected by a conducting wire

electrolysis or electrolytic cell

an electrochemical cell where a current is forced by a battery or an external source of energy

half cell reaction

oxidation or reduction at an electrode

anode

the electrode at which oxidation occurs

cathode

an electrode at which reduction occurs

reversible cell

a cell that is thermodynamic equilibrium

reversible cell

half cell reaction is reversed

standard hydrogen electrode or SHE

a platinum electrode coated with platinum black to catalyze electrode reaction

electrode potential E

potential of an electrode to a standard

electrode potential e

usaully the SHE

Electrode potential E

measure of driving force of electrode

Standard electrode potential

electrode potential measured in solutions

Standard electrode potential

all reactants and products ard in unit activity

theoretical cell potential

algebraic sum

Liquid Junction Potential

the potential that developed across a boundary

ohmic drop

developed when current flows in a electrochemical cell

ohmic drop

consequence of cell resistance

activation overpotential / overvoltage

additional potential to cause an electrode reaction

activation overpotential or overvoltage

result of an energy barrier

activation overpotential/ overvoltage

for gass evolution

concentration overpotential/concentration polarization

additional potential required to maintain a current flowing

LE COAST

Potentials

-Galvanic cell -electrolytic cell

types of electrochemical cell

electrochemical cell

consist of two conductors known as electrodes immersed in an electrolyte solution

salt bridge

isolates the reactants but maintains electrical contact

cathode

reduction occurs

anode

oxidation oocurs

-potential-current flowing thru it-resistance

chemical composition determines the ff

reference electrodes

independent of a solution composition and conditions

calomel electrode

consist of two concentric glass tubes, the inner contains mercury in contact with a paste of mercury (I) chloride (calomel) & potassium chloride

silver-silver chloride electrode

consists of a silver wire coated with silver chloride and incontact with silver solution of potassium chloride saturated with silver chloride.

electrolytic cell

consume electricity, requires external source of electrical energy for operation

galvaniv cell

store electrical energy

galvanic cell

batteries are made from such cells